Amazon.com has agreed to pay Microsoft an undisclosed sum as part of a patent cross-licensing deal between the companies announced on Monday.

The agreement gives each company access to the other's patent portfolio and covers a wide range of products and technologies, Microsoft said in a statement.

Among them, the agreement will shield Amazon from patent litigation against its Kindle e-reader, which includes some open-source software components, and against its use of Linux-based servers, Microsoft said.

Microsoft has asserted in the past that Linux and other open-source software may violate hundreds of its technology patents. The assertion angered open-source advocates, in part because Microsoft did not disclose the patents it said were being infringed.

Meanwhile, Microsoft has signed patent deals with several vendors that include coverage for their use of Linux and open source, including Novell, LG Electronics and Fuji Xerox. The deals are part of a broader IP licensing program that Microsoft kicked off in 2002.

Early last year Microsoft sued TomTom, a maker of in-car navigation systems, for allegedly violating eight of its patents, including three related to TomTom's implementation of Linux. TomTom paid to settle the suit.

Monday's statement doesn't refer to any specific Microsoft products covered by the Amazon agreement. Terms of the deal are confidential, Microsoft said, and a company spokesman declined to comment further.

Microsoft said its licensing program is designed to give other companies access to its research and development efforts and its growing portfolio of patents. It has entered into more than 600 licensing deals since 2002, it said.